Electron density in low density capillary plasma channel

A low density plasma channel of 1017cm−3 is created in a capillary discharge. The plasma channel is characterized through the hydrogen plasma spectra in the Balmer Hα line. The measured plasma density profiles were found to be in qualitative agreement with the hydrodynamic simulations. Guiding over many vacuum diffraction length using a plasma channel operating in the low density regime is demonstrated.